On the Formation of 2-Sulfonylbenzo[a]heptalene-1,3-diols as Precursors for the Synthesis of Colchicinoids
作者:Khaled Abou-Hadeed、Hans-Jürgen Hansen
DOI:10.1002/hlca.200390335
日期:2003.12
lithioalkyl sulfones suppresses the loss of HO−, and 4-methyl-2-sulfonylbenzo[a]heptalene-1,3-diols of type 4c have been isolated and characterized for the first time (Schemes 8 and 10). A number of X-ray crystal-structure analyses of starting materials and of the new benzo[a]heptalenes have been performed. Finally, benzo[a]heptalene 4c has been transformed into its 1,2,3-trimethoxy derivative 23, a benzo[a]heptalene
由4-[((R-磺酰基)乙酰基]庚烯-5-羧酸酯15和5-[(R-磺酰基)乙酰基]庚烯-4-羧酸酯16(R = Ph或吗啉代)形成苯并[ a ]庚烯。研究了R'SO 2 CH 2 Li和BuLi的存在(方案6)。根据其形成的一般机理,在形成的苯并[ a ]庚二烯-2,4-二醇3的C(3)处仅发现与庚烯骨架C(4)处的CO基团相连的磺酰基部分(方案3)。可能重新排列,以相应的2- sulfonylbenzo中间体[一个]庚搭烯-1,3-二醇失去HO -在反应条件下产生相应的11型环戊[ d ]庚酮(流程6和7)。然而,附加的Me基团中的C(存在α)的lithioalkyl砜抑制HO的损失- ,和4-甲基-2- sulfonylbenzo [一个]型的庚搭烯-1,3-二醇4C已被分离和首次进行特征化(方案8和10)。已经对起始原料和新的苯并[ a ]庚烷进行了许多X射线晶体结构分析。最后,苯并[